A step is applied to a first-order process at t = 0. The output starts at 0 and settles at 100. At t = 0.5 s it reads 60. Find the time constant τ.
Step response worksheet with answers
A first-order system G(s) = 2.5/(0.8s + 1) receives a step input of size 5 at t = 0, starting from rest. Find the output y(0.8) at t = 0.8 s.
A system has the transfer function G(s) = 291/(s² + 4s + 97) and receives a unit step input. Find the peak time tp of the step response.
A system has the transfer function G(s) = 28/(s² + 5s + 14) and receives a unit step input. The poles are s = σ ± jωd. Find the real part σ.
A mass m = 5 kg hangs on a spring k = 100 N/m with a viscous damper c = 13 N·s/m (m·x″ + c·x′ + k·x = F). At rest in equilibrium, a constant force F = 10 N is suddenly applied. Find the damping ratio ζ.
A unity negative feedback loop has G(s) = K/(s(s + 5)). Find the gain K that gives a step response with 25 % overshoot.
Answer key
- 1. τ = 0.5457 s
- 2. y(0.8) = 7.902
- 3. tp = 0.3258 s
- 4. σ = −2.5
- 5. ζ = 0.2907
- 6. K = 38.35
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